Lattice dynamics investigations of SiGe core-shell nanowires |
| |
Authors: | Y Zhang Y Xiao |
| |
Institution: | (1) Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, Xiangtan University, Xiangtan, 411105, P.R. China;(2) Department of Physics, Xiangtan University, Xiangtan, 411105, P.R. China |
| |
Abstract: | We present results from lattice dynamics calculations on the phonon modes and specific heat of SiGe core-shell nanowires.
The results show that phonon dispersion relation of SiGe nanowires consists of four acoustic branches. The frequency of the
first optical mode at Γ point shifts to low frequency as the Ge concentration is increasing. There are three strong peaks in the spectra of density
of states. The peaks at 9.0 THz and 15.0 THz can be attributed to the high frequency Ge-Ge and Si-Si bond vibration. The broad
peak around 3.0 THz of pure silicon nanowire corresponds to the transverse acoustic branch of bulk silicon. Moreover, specific
heat of SiGe nanowires increases (decreases) with the increase of the concentration x at low (high) temperature. The specific heat at 300 K can be fitted by C
V
= x
2
C
Ge + (1 − x)C
Si, where C
Ge and C
Si are specific heat of pure germanium and silicon nanowires respectively. |
| |
Keywords: | PACS" target="_blank">PACS 61 46 -w Nanoscale materials 61 48 De Structure of carbon nanotubes boron nanotubes and closely related graphitelike systems (for structure of hollow nanowires see 61 46 Np) 65 40 -b Thermal properties of crystalline solids |
本文献已被 SpringerLink 等数据库收录! |
|